The present invention relates to improvements in the driving train for straightening rolls arranged in an upper row and a lower row of the straightening machine.
Such a drive gear train has, on the one hand, a common input path, usually geared down for speed reduction from a relatively fast rotating motor; on the other hand, the drive gear train has a distributing portion to derive motive power for the several rolls from the common input. For this it is, for example, customary to associate each roll (with shaft) to an input gear and arrange them in groups of three, whereby one of the gears pertains to a roll of one of the rows and drives the two other gears of the group, both of which pertain to rolls of the other row.
Each of these roll drive gears, one per group, sits on a shaft which in turn is driven by a larger gear. These larger gears in turn are all interconnected and drivingly connect to the earlier mentioned common input path. For reasons of the physical arrangement of the rolls, these larger gears are also arranged in and along corresponding rows. As a consequence, some of these larger gears are driven directly by another one, others are driven by ones which in turn are driven by that other one. It was found, however, that this arrangement results in a rather unfavorable, nonuniform load distribution among these larger gears. In cases, the one larger gear whose shaft is the output of the common train portion has to transmit twice the actually needed power.